1. Field of the Invention
This invention generally relates to methods and apparatus for prosthetic implant devices. More particularly, the present invention relates to prosthetic implants for joints that include structure permitting the enhanced retention of the prosthetic implants.
2. Background Art
The replacement or augmentation of joints with artificial or prosthetic implants is well known in the field of orthopedics. Total knee arthroplasty (TKA) procedures involving the replacement of the knee joint are a good example. U.S. Publ. Appl. 2003/0028196A1 and the PFC RP Knee Replacement manual provide a good background for the techniques and devices used as part of these TKA procedures.
Most typically, a prosthetic implant is provided either with a long post or peg that is seated in a hole drilled into the longitudinal axis of the bone, such as for a tibial implant. In some cases, the peg is provided with a longitudinal fin running anterior-to-posterior that mates with a corresponding channel cut into the bone, such as for a femoral implant. U.S. Publ. Appl. 2003/0100953A1 describes a knee implant that has a pair of shaped pegs for the tibial implant and a longitudinal fin for the femoral implant that includes a peg with external recess features to assist in the fixation of the femoral implant. In one embodiment of the knee implant procedures described in U.S. Publ. Appl. 2003/0028916A1, a TKA femoral implant is described which utilizes a medio-laterally oriented protruding slot on the upper surface of the implant to interface with the femoral surface instead of a peg. The purpose and arrangement of this sideways oriented feature of this femoral implant is to permit the implant to be slid into place from a minimally invasive incision in either the lateral or medial side, as compared to the conventional approach where the major incisions for the TKA procedure are made primarily on the anterior (front) side of the knee.
It would be desirable to provide for an orthopedic prosthetic implant that could be implanted more consistently and effectively, yet be adaptable for implantation by minimally invasive procedures.